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STOCK INCENTIVE PLAN - Narrative (Details) - USD ($) $ in Thousands, shares in Millions |  | 12 Months Ended
--- | --- | ---
Nov. 21, 2019 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Compensation expense |  | $ 23,561 | $ 20,300 | $ 21,101
Employee service share-based compensation, tax benefit from compensation expense |  | 3,011 | 1,619 | 2,706
Selling, General and Administrative Expenses |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Compensation expense |  | $ 23,561 | $ 20,300 | $ 21,101
2020 Omnibus Incentive Plan |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Common stock reserved for future issuance (in shares) | 1.4 |  |  |
Life of awards | 10 years |  |  |

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